Outgoing Barcelona coach Luis Enrique turned on his misfiring stars after "reliving a nightmare" with his side's 3-0 humbling by Juventus in the first leg of their Champions League quarterfinal.

Barca produced the biggest Champions League comeback of all time in the last 16, overturning a 4-0 first leg deficit by scoring three times in a crazy final 10 minutes to beat the French champions 6-1, AFP reported.

However, a downcast and visibly angry Enrique said he found it "harder to believe in a comeback" than even the night in Paris that precipitated his decision to step down at the end of the season eight weeks ago.

"The first-half was a disaster, like it was the third half of the PSG game," said Enrique, who then took an out of character shot at the Barca players' attitude.

"I haven't been able to transmit my ideas well to my players because that was nothing like what I asked for. I feel very sad and impotent. What we saw was very serious.

"The positioning with the ball is my responsibility, but without it the intensity has to be different."

Enrique was filmed banging a table in his dugout in anger after watching a replay of Pablo Dybala's second goal in the first 22 minutes.

In a recurring theme of Barca's season Giorgio Chiellini then exposed a weakness from set-pieces to add Juventus' third just after halftime.

"Crucified," ran the headline of Barca daily Sport alongside a picture of Enrique.

"Very sad. Very serious," said the front cover of its rival Mundo Deportivo.

Enrique's announcement that he would not be renewing his contract a week after defeat in Paris appeared to have released the bubbling tension between players and coach as Barca's improved form provoked dreams of the possibility of a second treble in three seasons under the Asturian coach.

Indeed, after Saturday's 1-1 draw between Real Madrid and Atletico Madrid, Barca had the La Liga title race back in its own hands.

However, it kicked off a disastrous three days with a shock 2-0 defeat at Malaga to once again hand Real the initiative in the title race in which Neymar saw his first red card for the club.

And the Brazilian's sarcastic applause of the officials as he left the field has seen him hit with a three-match ban, meaning he will miss next weekend's potential title decider with Real at the Santiago Bernabeu.

Barca's hopes of a third straight Spanish title depend on winning that match, but defeat in Turin was just a continuation of the Catalans' poor away form this season.

It has now been beaten five times on the road in 2017 and has conceded at least three goals in three of its last four Champions League games away from home.

Producing another remarkable comeback against a Juventus defense that has conceded just twice in seven Champions League games this season seems even more unlikely than Barca's historic feat against PSG.

Yet, as bad as it has been away from the Camp Nou, the force of nearly 100,000 fans and a front three of Lionel Messi, Luis Suarez and Neymar means Juventus will not relish its trip to Catalonia in a weeks' time.

If there is any hope for Barca to cling to, it is that they have won all of four Champions League fixures at home this season by a combined 21 goals to one.